亡妹

ぼうまい

one's deceased younger sister

妹娘

いもうとむすめ

younger daughter

妹婿

いもうとむこ

the husband of one's younger sister

姉妹

しまい きょうだい

sisters

兄妹

けいまい きょうだい

older brother and younger sister

令妹

れいまい

your younger sister

実妹

じつまい

one's younger sister

妹背

couple; husband and wife; man and wife

義妹

ぎまい いもうと

sister-in-law (younger), stepsister

従妹

じゅうまい いとこ

cousin (younger female)

愚妹

ぐまい

younger sister

末妹

まつまい

youngest sister

弟妹

ていまい

younger brother and sister

小妹

しょうまい

little sister, younger sister

妹君

いもうとぎみ

(younger) sister

妹御

いもうとご いもとご

(another person's) younger sister

妹分

いもうとぶん

protegee, someone who one considers as a younger sister

吾妹

わぎも

my wife

継妹

ままいも

step-sister (younger), stepsister